Discharge mechanism for concrete mixers and analogous apparatus



June J. c. MERWIN ET AL 2,045,532

DISCHARGE MECHANISM FOR CONCRETE MIXERS AND ANALOGOUS APPARATUS Filed Feb. 24, 1952 Jhn afllerwinah LharlesEBall,

Patented June 23, 1936 g 2,045,532 nrscnnncn MECHANISM FOR CONCRETE MIXERS AND John 0. Merwin and can r. Ball,

ANALOGOUS APPARATUS Milwaukee,

Wis., assignors to Chain Belt Company, Milwaukee, Wis.,

a corporation of Wisconsin Application February 24,1932, Serial No.- 594,833

- '10 Claims.

This invention relates to discharge mechanism forconcrete mixers and analogous apparatus and has for one of its objects to provide a mechairism of this character which willbe simple in 5 construction, comparatively inexpensive to manufacture and more efllcient in use than those which have been heretofore proposed.

A futher object of the invention is to provide discharge mechanism which is particularly, al though not mixers of the truck or transit type and which will permit of dispensing with the usual removable closures for the discharge openings of such mixers, while. at the same time efiectively preventing discharge or leakage of the contents of the mixing receptacle'except when such discharge is desired.

A still further object oi! the invention is to provide a discharge mechanism which is espe- 2 cially adapted for use in connection with high discharge concrete mixers of the truck type and which secures an increase in the elevation of discharge over that heretofore attained. thereby securing a further increase in the chuting or spouting range. 1

With the above and other objects in view which will appear as the description proceeds, the invention consists in the novel details of construction and combinations of parts more fully pointed out in the appended claims.

Referring to the accompanying drawing forming a part of this specification in which like reference characters designatelike parts in all the views:

Figure 1 is a side elevational view of the rear portion of a truck or transit concrete mixer of the rotating drum type, illustrating discharge mechanism constructed in accordance present invention applied thereto;

Figure 2 is an enlarged vertical sectional view through the rear portion of the mixing recep- -tac1e and discharge mechanism shown 'in Figure 1; and

Figure 3 is altransverse sectional view taken approximately on the plane indicated by the line 3-3 of Figure 2, looking in the-direction of the arrows. I

'It is the usual practice in the operation of 50 truck or transit mixers of the rotating drum type which are provided with discharge openings in the" rear wall of the mixing receptacle "to charg'exthe cement adaggregates into the receptacle to a mien greater extent than is common in mixers of solely adapted for use with concrete hereinafter described and particularly with the the stationary and paving types wherein the charging and discharging openings of the mixing drum are normally open. That is to say, practically every making materials to in truck mixer practice the drums are in instance filled with concreteabove their rotative axis,

and in most cases they are substantially twothirds full. As a result of this practice of more fully charging the mixing receptacle it is neces-- sary in truck mixers to provide closure means for the discharge opening in order that during the mixing or agitating operation the mixture will not leak out or be through such opening. ally taken prematurely discharged Such closures have usuthe form of disks or; plates 'fitting is usually sealed and discharge openings are since the charging and likewise closed during mixing it has been found that excessive pressures have been built up within these receptacles as a result of gases formed through chemical action between the water and the cement during mixing and 'it has been necessary to provide means for venting the receptacles to the external atmosphere to prevent the violent blowing out of it is unlocked for through provision of suitable means for preventing discharge through the discharge opening same time eliminating during mixing while "at the the usual tightly sealed discharge closure maintains the interior of themixing receptacle in communication that any gases which may the mixing may readily find ternal atmosphere so be formed during with the extheir way to said atmosphere and the provision of special vents is therefore rendered unnecessary. It also permits of the introduction or the water necessary discharge opening,

-for the mix through the said eliminating the necessity for stufling-boxes or glands, as well as-for valves or protectors for the discharge end of the water pipes; and since the interior of the receptacle is always open, 'quired to get to'the atmosphere, the time rethe water into the receptacle is greatly reduced. Furthermore, through elimina tion of the closure for the discharge opening and its supporting and operating mechanisms,

considerable saving in may be effected.

the cost of construction .able transmission and reversing mechanism associated with an internal combustion engine or other source of power enclosed within a housing l2.

course obvious that if desired power for such drive may be derived from a power take-oil from the truck motor or from the truck transmission.

The drum 1 may be provided with a charging opening normally closed during mixing and discharge by a hatch cover l3 and the rear wall ll of the said drum has the usual axial discharge opening |5 surrounded by a bearing ring l6 constituting the rear journal for the drum. The interior of the drum] may also be provided with the usual mixing or agitating blades H which develop adjacent the discharge opening I5 into pick-up bucket formations II which are or may be of the type described and claimed in the co-pending application of Charles F. Ball,

filed June 24, 1931, Ser. No. 546,591, now Patent No. 2,006,728, granted July 2, 1935. As is customary in this type of apparatus the blades H are helically disposed within the receptacle so that during rotation of the drum in one direction they not only agitate the contents but also move it toward the forward end, while upon rotation in the opposite direction they reverse the end-wise movement and force the mixture toward the rear where it is picked up by the bucket formations l8 and carried to the discharge opening IS.

The discharge mechanism constituting the present invention as here shown comprises a tube or conduit 20, one end of which may pass Although the drum is here shown as being driven by an independent motor, it is of through the bearing ring |6, and into the discharge opening l5, as clearly shown in Figure 2, which tube or conduit may project rearwardly from the rear wall I! any suitable distance, say from 2 to 5 feet or more. This conduit 20 is preferably rotatable with the drum I and there is provided within the said conduit one or more helically disposed .baiiies or vanes 2| which may be welded or otherwise suitably secured to the inner surface of the tube 20. The said baflies 2| extend substantially radially inwardly from the inner surface of the tube and their inner edges are preferably secured to an axial core or tube 22, the ends of which are or may be closed as at 23. While not absolutely essential it is preferred to provide as many helical bailles v or vanes 2| as there are mixing blades within the drum and to arrange them as substantial continuations of said blades, and for the purposes of illustration three such baflles and blades have been herein indicated, although obviously a greater or less number may be employed as occasion may demand.- .The helical baifles 2| together with the core member 22 completely close the conduit 2|] against direct longitudinal movement of the material therethrough at all times; whether the receptacle 1 be stationary or rotating in either direction. On the other hand the elements 2| and 22 provide tortuous channels-24 within the conduit 20 through which the concrete mixture may find its way during discharge, as for example when the drum is rotatedin the direction of the arrow B of Figure 2 considerable distance into the at which time the mixing blades l1 and pick up buckets |8 will move the mixture toward the right as viewed in Figures 1 and 2 and discharge it into the said tortuous channels whereupon it will be picked up by the helical blades or baflles 2| and its movement toward the right further continued until it is discharged at the outer end of the conduit 20. When the drum is being rotated in the reverse direction indicated by the arrow A in Figure 2 for mixing purposes the said vanes or baiiies 2| will tend to move any material which may flnd its way to the. discharge opening toward the left as viewed in said figure and will thereby efl'ectively prevent leakage or undesired discharge of the mixer notwithstanding the fact that no tight removable closure is employed. At the same time the channels 24 provide adequate vents to the external atmosphere through which any gases formed through the hydration of the cement may find their way, as will be readily understood. 7

At the outer or discharge end of the tube or conduit 20 there is provided a chute or hopper 26 for guiding and directing the mixture intoa suitable trough or other conveyor 21 by means of which it may be conveyed to the point of use.

In as much as the discharge opening of the drum is at all times open to the atmosphere it is possible to introduce the water .necessary for the mix through said opening,'thereby eliminating the necessity for the useof stufling-boxes at the forward end of the drum, as has heretofore been the case where the water pipe was introduced through the front journal. For this purpose there is provided a water-receiving tank or receptacle 28 positioned adjacent the rear of the apparatus and above the conduit 20, see

Figure 1, from which receptacle a valved water pipe 29 may lead, the discharge end of which pipe may extend through the wall of the chute 26 so as to discharge water into the interior of 1 the conduit 20. If desired this pipe may be extended through the central tubular member 22 and into the interior of'the drum 1, or in some instances, said member 22 maybe employed as a portion of the water conduit by into the outer end thereof eifectively washes its [surfaces as well as those of the vanes 2| and core 22, preventing hardening and building-up of concrete deposits thereon. Furthermore, if the watersupply pipe is not extended into the drum the danger of clogging thereof through 'the hardening of the concrete mixture is eliminated, and it is also unnecessary in such case t provide any special valve or protector at the end of the water pipe for preventing entry of the concrete mixture into the pipe, as has been heretofore necessary where the pipe extended a mixing receptacle from the forward end.

While the present mechanism is adapted for use in connection with mixers of the rotating drum type in which the drum is mounted with its axis substantially horizontal it is of special importance in connection with theihigh disis accomplished through elevation of the rear 'end of the mixing unit as described and claimed in the cop'ending applicationoi Charles F. Ball, filed May 16, 1931, Serial No. 537,926, now Patent No. 1,998,749, granted April 23, 1935, or whetherthey be of the fixed, inclined axis type disclosed in the co-pending application of Charles F. Ball filed March 9, 1932, Serial No. 597,829, new Patent No. 2,018,112, granted October 22, 1935. For purposes of illustration the present invention has been shown as applied to the conoidal drum typehaving a fixed inclined axis such as that shown in the last mentioned application and as will be readily apparent from Figurea 1 and 2, the elevation of discharge may be. materially increased through the employment of the tube or conduit 29. The extent of this elevation will of course, depend upon the length of thesaid tube, which, may be varied within considerable limits as will be readily understood.

It is obvious that those skilled in the art may vary the details of construction as well as the precise arrangement of parts without departing from thespirit of the invention, and therefore it is not wished to belimited to the above disclosure except as may be required by the claims.

What we claim is: p

1. In concrete mixing and analogous apparatus having a rotatable agitation receptacle provided with a discharge opening, a perimetrically closed conduit open at both ends, secured to saidreceptacle in communication withand extending outwardly from said opening; and members within said conduit arranged to completely prevent direct axial discharge of the receptacle con tents when said receptacle is charged with material to a level above the axis of said discharge opening. 1' p a 2. In concrete mixing and analogous apparatus having a rotatable agitation receptacle provided with a discharge opening, a perimetrically closed conduit openat both ends, secured to said receptacle incommunication with and extending outwardly from said opening; and means-including bafiles within said conduit, arranged to transversely obstruct the same. to completely prevent direct axial discharge of the receptacle contents when said receptacle is charged with material to a level above the axis of said discharge opening, said bailies however providing indirect non-axial passages through which said contents may be discharged during the discharging operation.

3. In concrete mixing and analogous apparatus having a rotatable agitation'receptacle: provided with a discharge opening, an open-ended conduit secured to and rotatable with said recap- 'tacle, and extending from said openin and baflle memberswithin and rotatable with said conduit, providing tortuous passages through which the material may pass from the receptacle as the latter 'together with the conduit are rotated in one direction, said bailles however completely preventing direct longitudinal movement of the material through the conduit.

4. In concrete mixing and analogous apparatus having a rotatable agitation receptacle provided with an axial end discharge opening, .a perimetri- 'cally closed conduit open at bothends. secured to said receptaclein communication with and extending outwardly from said opening; and means including spaced helically disposed bai'lles secured withinsaid conduit, arrangedto transversely obsaid receptacle arranged through rotation in one 'ing an axial discharge opening in one end wall of struct the-same to completely. prevent direct axial discharge through said conduit or the receptacle contents when said receptacle is charged with materials to a level above the axis of said discharge opening, said bailies however providing helical passages open to the atmosphere through which said contents may pass during the discharging operation.

5. In concrete mixing and analogous apparatus having a rotatable agitation receptacleprovided with an axial end discharge opening, a perimetrically closed conduit open at both ends, secured to said receptacle in communication with and extending outwardly from said openin and means including a central core member surrounded by a plurality of helically disposed baiiles, secured within said'conduit and arranged said receptacle is charged withmaterials to a level 20 above the axis 01 said discharge opening, said core member and baiiles however providing hellcal passages open to the atmosphere through which said contents may pass duringthe discharging operation.

6. In concrete mixing and analogous apparatus having a rotatable agitation receptacle, provided with a discharge opening at one end, and agitating blades and pick-up buckets within direction to agitate and move the material away from said opening, and through rotation in the opposite direction to agitate and move the ma-' terial to and through said opening, the combination of atubular conduit secured to said receptacle for rotation therewith and extending outwardly from said discharge opening; and helical vanes within said conduit constituting continuations of said blades and buckets, ar-

ranged through rotation in saidflrst direction to-move-- any material tending to enter said con 'duit through said discharge opening back into' said receptacle thereby preventing leakage and undesired discharge, and through rotation in said other direction to receive material from said buckets and move it outwardly through said conduit to discharge the same. V

7. In a truck concrete mixer having a rotatable mixing receptacle provided with a discharge opening; an open-ended discharge conduit extending outwardly from said opening; means in saidconduit' arranged to prevent leakage and discharge'of the receptacle contents during the mixing operation while maintaining 5 open, communication between the interior of said receptacle and the atmosphere; awater tank carried by the truck; and connections between said tank and said discharge conduit for introducing water 8.- In a high-discharge concrete mixer, agitator and the like, arotatable agitation receptacle havsmallerdiameter than said receptacle, the rotative axis of said receptacle in its discharge position being inclined i'rom the. horizontal; a circumferentially closed conduit rotatable with said receptacle and extending axially outward from said opening, arranged to receive themixture from said opening and conduct it to a point 01' discharge which is higher than discharge would be from said opening; and means in said conduit for moving the therethroughl 9. In concrete mixlrig and analogous. apparatus,

a rotatable agitation receptacle having an end discharge opening and an axially extending wall;

a core member within said wall, disposed substantially parallel to but spaced therefrom; and a helical member disposed between said wall and core member, and forming therewith a perimetrically closed helical passage communicating with end discharge opening and a perlmetral wall extending from said opening; a tubular member disposed substantially co-axially of said opening; ,and a helical member intermediate said tubular member and wall with its respective edges secured thereto, said helical member serving to prevent straight-line discharge of the mixture through the space between the tubular member and wall, but being arranged to worm the mix;-

JOHN C. MERWIN. CHARLES F. BALL. 

